The present invention relates to time division multiplexed (TDM) communication systems, and more particularly, to control of such TDM systems via communications channels existing between multiple stations in a TDM network.
TDM systems provide a convenient method of transporting multiple channels of digital data via a single physical link. T1 and E1 are two exemplary TDM protocols well known to those in the art. The simplest form of a TDM communication system is a point to point system 10 with two TDM multiplexors 12 electrically coupled by some physical media 14 (e.g., an electrical cable), as shown in FIG. 1. Each TDM multiplexor can receive N discrete channels of channel data and transmit those channels in time-multiplexed slots arranged within consecutive frames. Further, each TDM multiplexor can receive transmitted frames and “de-multiplex” the data within the time-slots and distribute that data to the proper discrete channels. TDM multiplexors may also be used to form complex meshed networks combining ring and star topologies. Network access components such as multi-port switches and digital cross connect servers utilize TDM multiplexing functions to implement more complex network topologies.
Control of these access components within such networks is typically accomplished by connecting a personal computer or other terminal device 16 to a control port 18 on each access component via a standard communications link such as Ethernet, RS-232 or RS-485. Further, several co-located access components may be daisy-chained together by electrically coupling the respective control ports, thus providing a single access point for control management access.
One disadvantage to providing control to networked access components in this manner is the associated complication and expense, since each access component must include circuitry necessary to implement the interface to the standard communication link. Further, each terminal device 16 must be coordinated so that the control parameters are consistent throughout the network.
Another disadvantage to providing control to networked access components in this manner is the limited extendibility, since standard protocols such as Ethernet, RS-232 or RS-485 typically specify maximum transmission path lengths. Although implementing “repeater” stations in the control path can mitigate this extendibility problem, such repeaters increase the overall expense of the system.
It is an object of the present invention to substantially overcome the above-identified disadvantages and drawbacks of the prior art.